Yes, there are several religions that begin with the letter "S," including Sikhism, Shintoism, Santeria, and Scientology. Each of these religions has its own beliefs, practices, and followers.

usa

scientology

A Scientologist is an individual who practices Scientology as a religion. Scientology is a body of beliefs and related practices initially developed by Science Fiction author L. Ron Hubbard in 1952 as an outgrowth of his earlier self-help system, Dianetics.[1] Hubbard later characterized Scientology as an "applied religious philosophy" and the basis for a new religion.[1] Scientology encompasses a spiritual rehabilitation philosophy and techniques, and covers topics such as morals, ethics, detoxification, education and management.

http://www.scientology.org/

Rob Thomas, the American singer-songwriter, has not publicly stated his religious beliefs, so it is not definitively known what religion he practices.